Things like Soul Gems and Lockpicks are required, as well as any weapons or armor that you plan to use. I try to keep this as empty as possible but it is definitely wise to carry some much needed items wherever you go. All of your characters will start off with 60 inventory slots to fill with items from weapons to armor and all of the crafting materials. Your bag, or inventory, is the stuff that you carry around with you on your character.
You might be out in the world and find that you don’t have enough space to pick up that great item that you just found. To be a successful crafter in ESO also requires enough bag and bank space to store all of your crafting materials like ingots, upgrade materials, racial style materials and more. It might not seem like it but bag and bank space mismanagement can have repercussions for your character. In ESO bag and bank space management is an important part of character progression.